A girl who suffered severe burns as a 7-year-old in a fire deliberately set by her mother's ex-boyfriend spends her "free time sitting by herself" and wondering "why me?", a Windsor court heard Monday.

"Her days and weeks are filled with therapy and medical appointments," Isabel Rueda's father Jose Rueda said at the sentencing hearing for Kenneth Kormendy.

Kormendy was convicted in November of attempted murder and arson in connection with an October 2015 fire on Balfour Boulevard. 

He set the house ablaze while his ex-girlfriend, Sheri Rueda, was inside with her daughter Isabel and her other daughter, who was just 11-months-old.  Police say Kormendy smelled of gasoline and had a lighter in his pocket when he was arrested. 

Isabel suffered serious burns and continues to struggle, court heard. She has scars on her face and, with limited use of her right hand, has a difficult time writing and opening doors. She has had to wear compression garments over her face and she will require multiple surgeries.

"Her days and weeks are filled with therapy and medical appointments." - Jose Rueda, father of Isabel Rueda

Assistant Crown Attorney Walter Costa is seeking a life sentence for Kormendy, with no chance of parole for 10 years.

He called burning another person alive the "most barbaric form of killing" and said Kormendy resorted to the "barbaric and lethal action" when he discovered he could no longer control Sheri Rueda.

"Burning someone in that fashion is torture," said Costa. "You would face the fact you're facing your own death."

Kormendy's lawyer Helen Burgess asked the court for a 10-year sentence, stressing her client was a "productive member of society" without an extensive criminal record. 

Kormendy told the court his thoughts were with the injured girl and her family and that "sleep doesn't come easily to him."

He said he was innocent of the charges and planned to appeal. 

Kormendy's brother told the court in a letter his brother had always been a "kindhearted, polite, hard working man."

Kormendy's mother said her son was a "loving person" who would "never hurt a fly."